1. Field of the Invention
The present invention relates to a composition for external use (hereinafter referred to as an external-use composition), and more particularly, to an external-use composition useful as a cosmetic composition.
2. Background Art
Conventionally, a spherical powder of an organopolysiloxane elastomer, having characteristic elasticity, has been developed as a powder for cosmetic compositions and has been incorporated into a variety of products. Such a powder exhibits favorable properties when incorporated into cosmetic compositions, i.e., the cosmetic composition containing such a powder exhibits good skin fittability and spreadability on the skin; imparts a light and smooth sensation when applied by rubbing; has a soft-touch sensation; and imparts no strange sensation or irritation to the skin (Japanese Patent Application Laid-Open (kokai) No. 2-243612 and Japanese Patent Publication (kokoku) Nos. 4-17162 and 4-66446).
Meanwhile, a gelling agent for an oily ingredient is used in order to thicken an oily ingredient in an external-use composition. Conventionally, gelling agents such as metallic soap, organic-compound-modified clay minerals, and oil-soluble polymers have been known to gel hydrocarbon oils and ester oils. However, hydrocarbon oils and ester oils per se are sticky and oily, and such drawbacks limit use thereof in an external-use composition, even though gelling agents therefor are available.
In contrast, silicone oils, having favorable characteristics such as a light sensation for use and an non-sticky touch to the skin, has been widely used in external-use compositions in recent years. However, few gelling agents for gelling silicone oil are known; an example of which is a certain type of polyether-modified silicone disclosed in Japanese Patent Application Laid-Open (kokai) No. 7-215817. In addition, a gel-type composition in which silicone oil is gelled by use of the polyether-modified silicone exhibits slight stickiness which is characteristic to polymers.
In view of the foregoing, an object of the present invention is to provide an external-use composition imparting no sticky sensation in use, particularly an external-use composition for cosmetic compositions exhibiting excellent retention on the skin during use (hereinafter called xe2x80x9ccosmetic retentionxe2x80x9d), by finding a gelling agent for an oily ingredient, particularly for silicone oil.
In order to overcome the drawbacks, the present inventors have conducted earnest studies on a spherical powder of organopolysiloxane elastomer, and have found that a spherical powder of organopolysiloxane elastomer having a JIS A hardness as low as 1.0-30 has excellent oil-absorbability and serves as a gelling agent for an oily ingredient, particularly silicone oil, as compared with a conventionally used spherical powder of organopolysiloxane elastomer having a JIS A hardness of 35-80.
The inventors have also found that an external-use composition containing such a spherical powder of organopolysiloxane elastomer having excellent oil-absorbability imparts no sticky sensation in use and exhibits further improved skin fittability and spreadability on the skin; and imparts a further improved light and smooth sensation when applied by rubbing (hereinafter referred to as light and smooth application sensation), as compared with a conventionally used spherical powder of organopolysiloxane elastomer having a JIS A hardness of 35-80, and has excellent stability with the passage of time. Particularly, when the composition serves as a cosmetic composition, the cosmetic composition exhibits excellent cosmetic retention. The present invention has been accomplished based on this finding.
Accordingly, in one aspect of the present invention, there is provided an external-use composition containing a spherical powder of organopolysiloxane elastomer having a JIS A hardness of 1.0-30 that has a mean particle size of 0.1-200 xcexcm.
Preferably, the external-use composition contains the spherical powder of organopolysiloxane elastomer in an amount of 0.1-50.0 wt. % based on the entirety of the composition.
Particularly, the external-use composition is suitable for cosmetic compositions.
As used herein, the term xe2x80x9cmean particle sizexe2x80x9d refers to a value which is obtained by measuring the diameters in a specific direction of particles under an optical microscope and dividing the sum of respective diameters of particles by the number of measured particles.
The term xe2x80x9cJIS A hardnessxe2x80x9d refers to a hardness measured according to JIS K 6301 by use of the JIS A hardness meter.
The present invention provides an external-use composition having excellent spreadability on the skin, good light and smooth application sensation and skin fittability, and non-sticky sensation in use. Particularly, the present invention provides a cosmetic composition having greatly improved cosmetic retention.
Modes for carrying out the present invention will next be described.
The spherical powder of organopolysiloxane elastomer which is incorporated into the external-use composition of the present invention is composed of an organopolysiloxane elastomer having a JIS A hardness of 1.0-30, preferably 1.0-10. When the JIS A hardness is less than 1.0, the external-use composition containing the powder disadvantageously imparts a sticky sensation in use, whereas when the hardness is in excess of 30, gelling property of the powder is unfavorably markedly deteriorated.
The spherical powder of organopolysiloxane elastomer that is incorporated into the external-use composition of the present invention has a mean particle size of 0.1-200 xcexcm, preferably 0.5-20.0. When the particle size is less than 0.1 xcexcm, a smooth application sensation disadvantageously disappears, whereas when the particle size is in excess of 200 xcexcm, the powder causes an unfavorable rough sensation when applied by rubbing.
The spherical powder of organopolysiloxane elastomer which is incorporated into the external-use composition of the present invention may be a perfectly spherical powder or an oblate spherical powder. However, a perfect spherical powder is more preferable in that the composition containing the powder imparts a more favorable smoother application sensation.
No particular limitation is imposed on the method for producing the spherical powder (having a mean particle size of 0.1-200 xcexcm) of organopolysiloxane elastomer having a JIS A hardness of 1.0-30, and the powder can generally be produced by use of a curable organopolysiloxane composition as a raw material. Examples of the curable organopolysiloxane composition include:
an addition-curable organopolysiloxane composition which is cured through addition reaction between a diorganopolysiloxane having a silicon-bonded hydrogen atom and an organopolysiloxane having a silicon-bonded lower alkenyl group such as a vinyl group conducted in the presence of a platinum catalyst;
a condensation-curable organopolysiloxane composition which is cured through dehyrogenation reaction between a diorganopolysiloxane having hydroxyl groups at both molecule ends and a diorganopolysiloxane having a silicon-bonded hydrogen atom conducted in the presence of an organotin compound;
a condensation-curable organopolysiloxane composition which is cured through condensation reaction, such as dehydration or removal of alcohol, oxime, amine, amide, carboxylic acid, ketone, etc., between a diorganopolysiloxane having hydroxyl groups at both molecule ends and hydrolyzable organosilanes conducted in the presence of an organotin compound or titanate;
a peroxide-curable organopolysiloxane composition which is cured by the application of heat in the presence of an organic peroxide catalyst; and
a high-energy-ray-curable organopolysiloxane composition which is cured through radiation of xcex3-rays, UV-rays, or an electron beam.
Among these curable organopolysiloxane compositions, an addition-curable organopolysiloxane composition is preferred, in view of a high curing rate and homogeneity in curing. A particularly preferable composition comprises (A) a diorganopolysiloxane having at least two silicon-bonded hydrogen atoms in the molecule; (B) an organopolysiloxane having at least two lower alkenyl groups in the molecule; and (C) a platinum catalyst.
An organic group other than a lower alkenyl group may also bond to a silicon atom in an organopolysiloxane or a diorganopolysiloxane serving as a predominant component of the above-mentioned curable organopolysiloxane composition, and examples of such an organic group include an alkyl group such as methyl, ethyl, propyl, butyl, or octyl; a substituted alkyl group such as 2-phenylethyl, 2-phenylpropyl, 3,3,3-trifluoropropyl; an aryl group such as phenyl, tolyl, or xylyl; and a monovalent hydrocarbyl group having a substituent such as an epoxy, carboxylate, or mercapto group.
Several methods may be employed for producing the spherical powder (having a mean particle size of 0.1-200 xcexcm) of organopolysiloxane elastomer having a JIS A hardness of 1.0-30 from the above-mentioned curable organopolysiloxane composition. Examples of the methods include the following (1) to (4):
(1) a method which involves mixing an addition-curable, condensation-curable, or peroxide-curable organopolysiloxane composition with water in the presence of a surfactant such as a nonionic, anionic, cationic, or amphoteric surfactant; forming a homogeneous aqueous dispersion by use of an apparatus such as a homogenization mixer, a colloid mill, a homogenizer, or a propeller mixer; releasing the dispersion into hot water at 50xc2x0 C. or higher to thereby perform curing; and drying,
(2) a method which involves spraying an addition-curable, condensation-curable, or peroxide-curable organopolysiloxane composition directly into hot air-flow to thereby perform curing,
(3) a method which involves spraying a high-energy-ray-curable organopolysiloxane composition under exposure to high-energy rays to thereby perform curing, and
(4) a method which involves curing an addition-curable, condensation-curable, peroxide-curable, or high-energy-ray-curable organopolysiloxane composition and crushing the cured product by use of a known crushing apparatus such as a ball mill, an atomizer, a kneader, or a roll mill.
Of these, the method (1) is preferred in that a powder having a more spherical particle shape and a small variation in particle size can be produced.
A spherical powder of organopolysiloxane elastomer is described in detail in Japanese Patent Application Laid-Open (kokai) No. 2-243612 and Japanese Patent Publication (kokoku) Nos. 4-17162 and 4-66446.
The external-use composition according to the present invention contains the above-described spherical powder of organopolysiloxane elastomer in an amount of preferably 0.1-50.0 wt. % based on the entirety of the composition, particularly preferably 1.0-20.0 wt. %. When the content is less than 0.1 wt. %, an intended effect on improvement in use-related characteristics provided by the present invention, such as imparting no sticky sensation in use and a light and smooth application sensation, is poor, whereas when the content is in excess of 50.0 wt. %, the resultant external-use composition disadvantageously exhibits sluggish spreadability on the skin and imparts a rough sensation.
In addition to the above-described spherical powder of organopolysiloxane elastomer, a pigment powder may be incorporated into the external-use composition according to the present invention. No particular limitation is imposed on the pigment powder so long as it is one that is typically incorporated into an external-use composition, and any pigment powder such as an inorganic pigment powder or an organic pigment powder may be incorporated.
Example of the inorganic pigments include talc, kaolin, calcium carbonate, zinc flower, titanium dioxide, red iron oxide, yellow iron oxide, black iron oxide, ultramarine, titanium-coated mica, bismuth oxychloride, a binderg pigment, ultramarine pink, hydrated chromium oxide, titanated mica, chromium oxide, cobalt aluminum oxide, iron blue, carbon black, silicic anhydride, magnesium silicate, bentonite, mica, sericite, zirconium oxide, magnesium oxide, zinc oxide, titanium oxide, precipitated calcium carbonate, heavy calcium carbonate, light magnesium carbonate, heavy magnesium carbonate, and calamine.
Examples of the organic pigments include polyester, polymethylmethacrylate, cellulose, Nylon-12, Nylon-6, styrene.acrylic acid copolymers, polypropylene, poly(vinyl chloride), nylon powder, polyethylene powder, benzoguanamine powder, tetrafluoroethylene powder, boron nitride, fish scale flake, lake tar pigments, lake natural pigments, and inorganic-organic hybrid pigments.
Preferably, the pigment powder is hydrophobicized. No particular limitation is imposed on the hydrophobicized pigment powder so long as the powder has a hydrophobic surface. Examples of such powders include a pigment powder surface-treated with high-viscosity silicone; a pigment powder coated with a silicone resin which has been preliminary reacted with alkyl hydrogen polysiloxane; silicone-coated powder further treated with alkene; a pigment powder treated with one or more surfactants selected from a cationic surfactant, an anionic surfactant, and a nonionic surfactant; a wax-coated pigment powder; a pigment powder treated with dextrinized fatty acid; and a pigment powder treated with a fluorine compound containing a perfluoroalkyl group.
The external-use composition according to the present invention contains powders including the above-described spherical powder of organopolysiloxane elastomer in an amount of 0.1-60.0 wt. % based on the entirety of the composition, particularly preferably 1.0-40.0 wt. %.
The external-use composition according to the present invention may be used as a cosmetic composition, a drug composition, a quasi-drug composition, etc. When the external-use composition according to the present invention is used as a make-up cosmetic composition such as a foundation, advantages of the present invention are particularly notable, as the above-described spherical powder of organopolysiloxane elastomer absorbs sebum to thereby provide a cosmetic composition exhibiting excellent cosmetic retention.
The form of the external-use composition according to the present invention is not particularly limited, and the composition may be used in the forms of liquid, milky-lotion, ointment, cream, gel, etc., so long as the composition is applicable to the skin.
In addition to powders including the above-described spherical powder of organopolysiloxane elastomer, one or more ingredients which are typically added to an external-use composition, such as an oily ingredient or water, may be incorporated into the external-use composition according to the present invention without impairing the effects of the present invention and in accordance with the form.
Examples of the oily ingredient which is incorporated into the external-use composition according to the present invention include:
silicone oils such as dimethylpolysiloxane, dimethylcyclopolysiloxane, methylphenyl polysiloxane, methyl hydrogen polysiloxane, higher fatty acid-modified organopolysiloxane, higher alcohol-modified organopolysiloxane, trimethylsiloxysilicate, and decamethylcyclopentanesiloxane;
hydrocarbon oils such as liquid paraffin, squalane, vaseline, polyisobutylene, and microcrystalline wax;
ester oils such as isopropyl myristate, myristyl octyldodecanol, and di(2-ethylhexyl) succinate;
glycerides such as neopentyl glycol diisooctanoate, glyceryl monostearate, triglyceryl monoisostearate, and triglyceryl cocoate;
oils and fats such as castor oil and olive oil;
lower alcohols such as ethanol;
higher alcohols such as octyldodecanol, hexadecyl alcohol, cetyl alcohol, oleyl alcohol, stearyl alcohol, and polyethylene glycol;
higher fatty acids such as lauric acid, palmitic acid, oleic acid, stearic acid, and isostearic acid;
waxes such as lanolin and beeswax; and
fluorocarbon oils.
Such oily ingredients are preferably incorporated in an amount of 10.0-95.0 wt. % based on the entirety of the composition.
When the external-use composition according to the present invention is emulsified, the water content of the composition is typically 1.0-80.0 wt. % based on the entirety of the composition.
Other additives may also be incorporated into the external-use composition according to the present invention, so long as the effects of the present invention are not impaired.
Examples of such additives include
humectants such as polyhydric alcohol (e.g., glycerin), mucopolysaccharides (e.g., sodium hyaluronate), and organic acids and salts thereof (e.g., amino acids, amino acid salts, and hydroxy acid salts);
surfactants such as cationic surfactants, anionic surfactants, and nonionic surfactants;
pharmaceuticals such as vitamin E and vitamin E acetate;
astringents; antioxidants; preservatives; perfume; pH regulators such as sodium secondary phosphate; clay minerals; thickeners; and ultraviolet absorbents.
Of these, a humectant is preferably incorporated into the composition in order to prevent evaporation of water from the external-use composition per se.